WORLD OF INDUSTRIES - MOTION, DRIVE & AUTOMATION 3/2017

High performance safety

High performance safety brakes for robotic applications For applications in robotics and automation, the company, Mayr power transmission has not just developed the high-performance safety brakes, but is amongst the very few companies who are equipped with comprehensive testing facilities. construction shape and low weight have been tailored to the requirements for robotics applications, and are easily able to withstand the demanding application conditions. After power switchoff or failure, the brakes ensure reliable and safe holding of the axes in any position, thus guaranteeing maximum operating safety. Brakes for demanding applications MACHINE ELEMENTS For robot brakes, careful tests and inspections are not just important and increasingly in demand, but they have always been the central component of Mayr power transmission’s product development philosophy. Testing possibilities for robot brakes ensures that the design makes no compromises on safety of people and machines. The family owned company is one of the few manufacturers able to utilise decades of experience and engineering knowhow,and is also equipped with comprehensive testing possibilities. During the development of lightweight brakes for robotics applications, Mayr was able to make use of years of collaboration with the ‘Deutsche Zentrum für Luft-und Raumfahrt’ (German Aerospace Centre). “The lightweight brakes which came into existence almost 20 years ago over the course of the LBR II research project have established themselves today as a marketable standard solution, and prove their worth daily in countless robotics applications across the world”, explains Bernd Kees, Product Manager at Mayr. “The challenge today is to effectively serve very different installation situations through an expedient modular principle”. Therefore, the Roba - servostop safety brakes with their extremely slim Roba - servostop safety brakes feature extremely short switching times and guarantee reliable, constant holding torques across their entire lifetime. They have high performance density, are wearresistant and can also be used in demanding operating conditions, when temperatures within a motor reach 120 °C. The brakes are also characterised by their high reliable friction work during dynamic braking processes. And even at very high speeds, they are able to perform dynamic braking work across their entire lifetime. The simple and robust design of the safety brakes permits simple, fast and reliable assembly. The operating air gap is specified at the manufacturer’s works. In contrast to permanent magnetic brakes, exact axial positioning on the motor shaft is not required. The Roba - servostop brakes always work accurately and reliably; the magnetic air gap is not influenced by the mechanical installation situation. Quality corresponds to safety At the moment, brakes which are not even able to reach the nominal torque specified in the catalogue can be found in the market. Mayr, on the other hand, provides brakes which reliably guaran- WORLDOFINDUSTRIES – MOTION, DRIVE & AUTOMATION 3/2017

For any robotic application, large, small or highly precise like in medical technology, brakes from Mayr guarantees the reliable protection of people and materials 01 With their extremely slim construction shape and low weight, the Roba- servostop safety brakes have been tailored to the requirements of robotics 02 Maximum safety, comprehensive testing and inspection, have been central components of Mayr’s understanding of safety and quality tee maximum operating safety. For this purpose, the company always ensures careful quality control: not only because there are currently increased requirements for comprehensive tests and controls in the field of robotics, but rather because these have always been central components of Mayr’s concept of safety and quality. They ensure that the values stated in the catalogue are also reliably achieved. In the context of brakes, quality of brakes corresponds to its safety. Therefore, quality is always a major concern for end users. “Through our comprehensive testing possibilities, our knowhow and our years of experience, we are in a position to make reliable statements”, emphasises Bernd Kees. Additionally, the experience and the information from the tests also flow into the development of the products, so that these achieve an extremely high quality. A final round of inspection In addition to numerous quality assurance measures during the design process, Mayr also conducts a comprehensive final inspection. Here every single safety brake, which leaves the works, is first subjected to complete assembly and adjustment in a 100 % inspection. “We have designed our own final inspection test bench specially for our small robot brakes”, explains Rudolf Rädel, Design Engineer at Mayr power transmission. “On this test bench, we can conduct a torque inspection from 0.5 to 5 Nm. We begin the About Mayr Power Transmission The family-owned company, Mayr power transmission, founded in 1897, is a leading manufacturer of safety brakes, torque limiters and shaft couplings. These products are primarily used for electrically powered machines in filling plants, machine tools, packaging machines as well as in elevators, wind power plants, in stage technology and industrial robotics. Approximately 600 employees currently work in the Allgäu-based Headquarters in Mauerstetten, Germany. Mayr power transmission has over 1 000 employees worldwide. The company is globally established with plants in Poland and China, sales subsidiaries in the USA, France, Great Britain, Italy, Singapore and Switzerland and with representatives in 36 other countries. testing process by conditioning the friction linings, i.e. we leave the brakes to run in for a defined period of time, with their respective braking torque, in clockwise and anti-clockwise rotation”. Then the static and dynamic braking torques are inspected. “Regarding the dynamic braking torque, we inspect both the level and the torque ripple, i.e. the homogeneity of the torque”, says Georg Fichtl from Electronics Development at Mayr. In addition, the pull-in and dropout currents are determined on this final inspection test bench. “We want to obtain a realistic record of what actually happens in a customer’s application”, explains Georg Fichtl. “For this reason, we simulate real application conditions, and can for example heat the test bench upto 80 °C depending on the requirements and application”. Brakes for large robot applications The tried and tested modular ‘Roba - topstop’ brake systems for mounting onto servomotors are used in large robot applications. In gravity-loaded axes, these brakes ensure the safety of people and materials and therefore have to perform their work highly reliably. Mayr power transmission has voluntarily subjected the ‘Roba - topstop’ safety brakes to a prototype inspection through the ‘Deutsche Gesetzliche Unfallversicherung’ (DGUV – German Statutory Accident Insurance). They confirmed the brake device as a “tried and tested component” in terms of category 1 acc. DIN EN ISO 13849-1. And the company has developed its own final inspection test bench for these safety brakes as well. On this test bench, function-relevant parameters such as pull-in and drop-out voltage, coil resistance, dielectric strength of the coil and the proper function of the switching condition monitoring are determined. “In addition, the brake is also tested under high voltage for shorted coils. We also measure the clockwise and anti-clockwise torque”, says Rudolf Rädel on the testing possibilities. “The target values for these tests are derived from the system, i.e. the system knows what the brake should be able to perform. We always have identical, standardised measuring conditions. In case of safety-critical applications, it is important that the braking torque is correct. We could detect deviations in torque measurements immediately. Here, we can make reliable statements. The brakes fulfil the assured characteristics”. All the measurement values determined are archived together with the associated serial number of the brake in an electronic database. This guarantees 100 % traceability. So that the brakes from Mayr permanently provide the required safety, the company therefore focuses on clear processes, comprehensive testing possibilities, years of experience and highly-qualified employees. Bernd Kees rightly concludes: “As reliable partners, we have to offer products on which people can depend – as safety does not allow for compromises.” Photographs: Fotolia, Mayr power transmission www.mayr.com WORLDOFINDUSTRIES – MOTION, DRIVE & AUTOMATION 3/2017